Moisture separation heater

ABSTRACT

A hygroscopic moisture separating and heating apparatus ( 20 ) comprises a main body container ( 1 ) having a cylindrical shape, a partition plate ( 5 ) provided to define a space together with an inner circumferential face of the main body container ( 1 ) and configured to divide the internal space of the main body container ( 1 ) into a lower temperature area ( 30 ) and a higher temperature area ( 31 ), a steam inlet ( 6 ) provided to the lower temperature area ( 30 ) of the main body container ( 1 ), a steam outlet ( 7 ) provided to the higher temperature area ( 31 ) of the main body container ( 1 ), a hygroscopic moisture separator ( 8 ) located in the lower temperature area ( 30 ) of the main body container ( 1 ), and a U-shaped pipe ( 2 ) through which heated steam for heating the steam to be heated is fed. The U-shaped pipe includes an advancing part ( 21 ), a retracting part ( 22 ), and a U-shaped part ( 23 ) connecting the advancing part ( 21 ) with the retracting part ( 22 ). Either of the advancing part ( 21 ) and the retracting part ( 22 ) of the U-shaped pipe ( 2 ) extends through the partition plate across the lower temperature area ( 30 ) and the higher temperature area ( 31 ).

FIELD OF THE INVENTION

The present invention relates to a hygroscopic moisture separating andheating apparatus adapted to remove hygroscopic moisture from steam withhigher humidity and heat the steam by using heated steam.

BACKGROUND ART

Generally, in an atomic power plant, steam having finished its task in ahigh pressure turbine contains approximately 12% hygroscopic moisture.The hygroscopic moisture is typically present in a state of water dropscontained in the steam or water adhered to wall surfaces of theapparatus and piping.

When the hydroscopic moisture content in the steam is considerablyincreased, the hygroscopic moisture may tend to frequently collide withwall surfaces of apparatuses, such as a turbine blade installed in theturbine, thus causing erosion that may leads to serious damage of theequipment. In a low pressure turbine, the turbine efficiency becomeshigher as the humidity of the steam fed to the low pressure turbine isgreater.

To solve this problem, a hygroscopic moisture separating and heatingapparatus for separating the hygroscopic moisture from steam and heatingthe steam has been provided between the high pressure turbine and thelow pressure turbine, in order to remove the hygroscopic moisture fromthe steam fed from the high pressure turbine, heat the removed steam,and feed the so-heated higher temperature steam into the low pressureturbine. As the hygroscopic moisture separating and heating apparatus ofthis type, examples of the construction are described in, for example,JP2-242001A and JP9-329302A.

A conventional hygroscopic moisture separating and heating apparatus isnow described with reference to FIGS. 9 and 10. FIG. 9 is a lateralcross section showing a construction of the conventional hygroscopicmoisture separating and heating apparatus 70, and FIG. 10 is alongitudinal cross section of the hygroscopic moisture separating andheating apparatus taken along line E-E of FIG. 9.

As shown in FIGS. 9 and 10, the hygroscopic moisture separating andheating apparatus 70 includes a main body container 51 having a lateraland cylindrical shape, a hygroscopic moisture separator 58 incorporatedin the main body container 51 and adapted to remove hygroscopic moisturefrom steam 85 to be heated, and U-shaped pipes 52 each located above thehygroscopic moisture separator 58 and adapted to heat the steam 85 to beheated.

In such a construction, the hygroscopic moisture separating and heatingapparatus 70 is located to be symmetrical about an imaginary centralplane F-F defined at the longitudinal center of the main body container51.

Through each U-shaped pipe 52, heated steam 86 for heating the steam 85to be heated is fed. As the heated steam 86, extraction steam suppliedfrom the high pressure turbine of the atomic power plant or main steamsupplied from a nuclear reactor can be mentioned.

Each U-shaped pipe 52 includes an advancing part 521, a retracting part522 located below the advancing part 521, and a U-shaped part 523connecting the advancing part 521 with the retracting part 522. EachU-shaped pipe 52 is attached to a header 53 so as to constitute eachpipe bundle 54, wherein the header 53 is located outside the main bodycontainer 51 and adapted to supply and discharge the heated steam 86.

Below the main body container 51, for example, three hygroscopicmoisture separators 58 are located along the longitudinal direction.

Steam inlets 56, though which the steam 85 to be heated is fed into themain body container 51, are provided at a bottom portion of thecontainer 51, and steam outlets 57, through which the steam 85 to beheated is discharged from the main body container 51, are provided at atop portion of the container 51.

The steam 85 to be heated, which was fed from the high pressure turbineand supplied into the main body container 51 via each steam inlet 56,passes through each hygroscopic moisture separator 58, so that thehygroscopic moisture can be removed from the steam 85. Thereafter, thesteam 85 to be heated is flowed in the main body container 51 upwardorthogonally to the advancing part 521 and the retracting part 522 ofthe U-shaped pipe 52. Consequently, the steam 85 to be heated can beheated due to the heating steam 86 flowed through the U-shape pipe 52,and is then discharged from the main body container 51 via each steamoutlet 57. Chain line arrows, as depicted in FIG. 10, for expressing thesteam 85 to be heated, respectively designate directions in which thesteam 85 to be heated is flowed in the main body container 51.

In the conventional hygroscopic moisture separating and heatingapparatus 70, however, the temperature of the steam 85 to be heatedbecomes higher as it is flowed upward. Therefore, a temperaturedifference should occur between the advancing part 521 and theretracting part 522 in the U-shaped pipe 52, thus causing asignificantly great difference in the amount of condensation of theheated steam 86 in the U-shaped pipe 52 due to cooling.

Namely, in the retracting part 522 of the U-shaped pipe 52, thetemperature of the steam 85 to be heated in contact therewith is stillrelatively low. Therefore, the heated steam 86 flowed in the retractingpart 522 may be unduly cooled, thus causing excessively rapidcondensation. On the other hand, in the advancing part 521 of theU-shaped pipe 52, the temperature of the steam 85 to be heated incontact therewith is higher, as compared with the case of theaforementioned lower retracting part 522. Thus, the degree of beingcooled for the heated steam 86 flowed in the advancing part 521 issignificantly lower, as such a greater amount of the steam remainsuncondensed.

In such a state, the flow rate distribution of the heated steam 86 inthe U-shaped pipe 52 is likely to be unstable, and a periodictemperature change may tend to occur in the U-shaped pipe 52, leading todamage of the U-shaped pipe 52 due to thermal fatigue.

To avoid this problem, a method has been employed, in which a ventingpipe (not shown) for venting non-condensable steam of the heated steam86 is connected with an inlet portion of the U-shaped pipe 52, such thatabout 5% of the total amount of the heated steam 86 prior to being fedinto the venting pipe can be directed into the venting pipe.

However, if the amount (or venting flow rate) of the heated steam 86 tobe fed into the venting pipe is considerably large, the amount of theheated steam 86 fed into the U-shaped pipe 52 is of course reduced, thusdegrading the thermal efficiency of the entire hygroscopic moistureseparating and heating apparatus 70. Therefore, there is a need forreducing the venting flow rate.

SUMMARY OF THE INVENTION

The present invention was made in view of such circumstances, and it istherefore an object of this invention to provide a hygroscopic moistureseparating and heating apparatus, which can securely enhance the thermalefficiency, by employing such a construction that can avoid damage ofthe U-shaped pipe due to thermal fatigue caused by the difference in theamount of condensation in the U-shaped pipe, thereby stabilizing theflowing condition of the heated steam flowed through the U-shaped pipeeven though significantly reducing the venting amount of the heatedsteam fed into the venting pipe.

The present invention is a hygroscopic moisture separating and heatingapparatus for separating a hygroscopic moisture from a steam to beheated and heating the steam to be heated, comprising: a main bodycontainer having a cylindrical shape; a partition plate provided, in themain body container, to define a space together with an innercircumferential face of the main body container and configured to dividethe internal space of the main body container into a lower temperaturearea and a higher temperature area; a steam inlet, which is provided tothe lower temperature area of the main body container and through whichsteam to be heated is fed into the main body container; and a steamoutlet, which is provided to the higher temperature area of the mainbody container and through which the steam to be heated is dischargedfrom the main body container; a hygroscopic moisture separator locatedin the lower temperature area of the main body container and adapted toseparate hygroscopic moisture from the steam to be heated, which is fedinto the lower temperature area via the steam inlet; and a U-shaped pipeprovided in the main body container and including an advancing part, aretracting part and a U-shaped part connecting the advancing part withthe retracting part, such that heated steam for heating the steam to beheated is fed through the U-shaped pipe, wherein either of the advancingpart and the retracting part of the U-shaped pipe extends through thepartition plate across the lower temperature area and the highertemperature area.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that the partition plate is provided orthogonallyto the longitudinal direction of the main body container, and that theadvancing part and the retracting part of the U-shaped pipe are arrangedparallel to the longitudinal direction of the main body container.

The present invention is a hygroscopic moisture separating and heatingapparatus for separating a hygroscopic moisture from a steam to beheated and heating the steam to be heated, comprising: a main bodycontainer having a cylindrical shape; a first partition plate providedin the main body container orthogonally to the longitudinal direction ofthe main body container and configured to divide the internal space ofthe main body container into two or more mutually independent areas; asecond partition plate provided, in the main body container, to define aspace together with an inner circumferential face of the main bodycontainer and configured to extend orthogonally to the first partitionplate and divide each independent area of the main body container into alower temperature area and a higher temperature area; steam inlets eachprovided to each lower temperature area of the main body container, suchthat steam to be heated is fed into the main body container through thesteam inlet; steam outlets each provided to each higher temperature areaof the main body container, such that the steam to be heated isdischarged from the main body container through the steam outlet;hygroscopic moisture separators each located in each lower temperaturearea of the main body container and adapted to separate hygroscopicmoisture from the steam to be heated fed into the lower temperature areavia each steam inlet; and U-shaped pipes each provided in eachindependent area of the main body container and including an advancingpart, a retracting part and a U-shaped part connecting the advancingpart with the retracting part, such that heated steam for heating thesteam to be heated is fed through the U-shaped pipe, wherein the lowertemperature area of one independent area is adjacent to the highertemperature area of the other independent area, and wherein either ofthe advancing part and the retracting part of each U-shaped pipe extendsthrough the second partition plate across each lower temperature areaand each higher temperature area.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that the hygroscopic moisture separating andheating apparatus further comprises: a venting pipe connected with aninlet portion of the U-shaped pipe and adapted for venting the heatedsteam; and a pressure control valve or fluid resistor provided to theventing pipe, wherein the pressure control valve or fluid resistorcontrols the venting flow rate of the heated steam fed into the ventingpipe within the range of 0.5 to 1% of the total flow rate measuredbefore the heated steam is vented.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that a plurality of U-shaped pipes are provided;and that each U-shaped pipe is attached to a header so as to constitutetogether a pipe bundle, the header being provided outside the main bodycontainer and adapted to supply and discharge the heated steam, and thatthe header of one pipe bundle is attached to the main body container, ina position opposed to the header of the other pipe bundle locatedadjacent the one pipe bundle.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that the plurality of pipe bundles are located ina plurality of independent groups connected in series with one another,and the pipe bundles in each group are connected in parallel to oneanother, with the number of the pipe bundles in each group being reducedas the heated steam is flowed from the upstream to the downstream, andthat a drain tank is provided, which is adapted for accumulatingcondensed drain generated due to the heated steam cooled by the steam tobe heated, in each U-shaped pipe, wherein the drain tank is connectedwith the header of each pipe bundle via a drain pipe.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that a part of the condensed drain fed to thedrain tank via the drain pipe from each header is fed into each highertemperature area of the main body container through a drain feed pipe,so as to cool the higher temperature area.

In the hygroscopic moisture separating and heating apparatus describedabove, it is preferred that the pipe bundles are prepared by assemblingthe plurality of U-shaped pipes and headers in advance in a factory, andthen attached to the main body container on a site of installing theapparatus.

According to the present invention, in the hygroscopic moistureseparating and heating apparatus, by lessening the temperaturedifference at each portion in the U-shaped pipe, damage of the U-shapedpipe caused by thermal fatigue due to difference of the amount ofcondensation of heated steam flowed through the U-shaped pipe can besuppressed, thus providing a construction in which the flow of theheated steam through the U-shaped pipe will not be unstable even thoughsignificantly reducing the venting flow rate of the heated steam fedinto the venting pipe, thereby enhancing the thermal efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a construction of a hygroscopic moistureseparating and heating apparatus of a first embodiment when viewed fromabove.

FIG. 2 is a lateral cross section of the hygroscopic moisture separatingand heating apparatus taken along line A-A of FIG. 1.

FIG. 3 is a longitudinal cross section of the hygroscopic moistureseparating and heating apparatus taken along line B-B of FIG. 1.

FIG. 4 is an illustration showing temperature change of steam to beheated, wherein the steam is in contact with an advancing part and aretracting part of a U-shaped pipe in a main body container of thehygroscopic moisture separating and heating apparatus of FIG. 1.

FIG. 5 is a top view showing a construction of the hygroscopic moistureseparating and heating apparatus of a second embodiment when viewed fromabove.

FIG. 6 is a longitudinal cross section of the hygroscopic moistureseparating and heating apparatus taken along line C-C of FIG. 5.

FIG. 7 is a lateral cross section showing a supply route for supplyingheated steam to the U-shaped pipe of the hygroscopic moisture separatingand heating apparatus of a third embodiment.

FIG. 8 is a longitudinal cross section of the supply route for theheated steam taken along line D-D of FIG. 7.

FIG. 9 is a lateral cross section showing a construction of aconventional hygroscopic moisture separating and heating apparatus.

FIG. 10 is a longitudinal cross section of the hygroscopic moistureseparating and heating apparatus taken along line E-E of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT First Embodiment

Now, a first embodiment will be described with reference to FIGS. 1 to4.

FIG. 1 is a top view showing a construction of a hygroscopic moistureseparating and heating apparatus 20 of the first embodiment when viewedfrom above, and FIG. 2 is a lateral cross section of the hygroscopicmoisture separating and heating apparatus 20 taken along line A-A ofFIG. 1. FIG. 3 is a longitudinal cross section of the hygroscopicmoisture separating and heating apparatus 20 taken along line B-B ofFIG. 1. FIG. 4 is an illustration showing temperature change of steam 35to be heated, wherein the steam is in contact with an advancing part 21and a retracting part 22 of a U-shaped pipe 2 in a main body container1.

As shown in FIGS. 1 to 3, the hygroscopic moisture separating andheating apparatus 20 includes the main body container 1 having a lateraland cylindrical shape, a partition plate 5 provided, in the main bodycontainer 1, to define a space 32 together with an inner circumferentialface of a ceiling of the main body container 1 and configured to dividethe internal space of the main body container 1 into a lower temperaturearea 30 and a higher temperature area 31, a steam inlet 6, which isprovided below the lower temperature area 30 of the main body container1 and through which the steam 35 to be heated is fed into the main bodycontainer 1, and a steam outlet 7, which is provided below the highertemperature area 31 of the main body container 1 and through which thesteam 35 to be heated is discharged from the main body container 1. Ahygroscopic moisture separator 8 is located in the lower temperaturearea 30 of the main body container 1, the separator 8 being adapted toseparate hygroscopic moisture from the steam 35 to be heated, which isfed into the lower temperature area 30 from the steam inlet 6. Inaddition, the U-shaped pipe 2 is provided in the main body container 1.Through the U-shaped pipe 2, heated steam 36 is fed so as to heat thesteam 35, which has passed through the hygroscopic moisture separator 8and from which the hygroscopic moisture has been separated.

Chain line arrows, as depicted in FIGS. 2 and 3, for expressing thesteam 35 to be heated, designate, respectively, the directions in whichthe steam 35 to be heated is flowed in the main body container 1.

The partition plate 5, as shown in FIGS. 1 and 2, is provided at thelongitudinal center of the main body container 1, orthogonally to thelongitudinal direction.

The U-shaped pipe 2 includes the advancing part 21, the retracting part22 located below the advancing part 21, and a U-shaped part 23connecting the advancing part 21 with the retracting part 22. Theadvancing part 21 and retracting part 22 of the U-shaped pipe 2 areconfigured to extend parallel to the longitudinal direction of the mainbody container 1.

The length of the advancing part 21 and retracting part 22 of theU-shaped pipe is substantially the same as the length of the main bodycontainer 1.

Either of the advancing part 21 and the retracting part 22 of theU-shape pipe 2 is configured to extend through the partition plate 5across the lower temperature area 30 and the higher temperature area 31.

As shown in FIG. 2, the advancing part 21 include a lower temperatureadvancing part 211 located in the lower temperature area 30 and a highertemperature advancing part 212 located in the higher temperature area31, while the retracting part 22 includes a lower temperature arearetracting part 221 located in the lower temperature area 30 and ahigher temperature area retracting part 222 located in the highertemperature area 31.

In this embodiment, a plurality of U-shaped pipes 2 are provided in themain body container 1, and each U-shaped pipe 2 is attached to a header3 so as to constitute together a pipe bundle 4, wherein the header 3 islocated outside the main body container 1 and adapted to supply anddischarge the heated steam 36. For Example, the pipe bundle 4, as shownin FIG. 1, is provided in three sets, and the height of each pipe bundle4 is substantially the same.

As shown in FIG. 1, the header 3 of one pipe bundle 4 is attached to themain body container 1 in a position opposed to the header 3 of the otheradjacent bundle 4. According to the present invention, the temperaturedistribution along in the longitudinal direction of the main bodycontainer 1 can be uniformed as compared with the case in which all ofthe headers 3 of the pipe bundles 4 are provided to the main bodycontainer 1 on the same side.

A venting pipe (not shown) for venting non-condensable steam of theheated steam 36 is connected with an inlet portion of each U-shaped pipe2, and a pressure control valve (not shown) is provided to the ventingpipe.

The pressure control valve functions to control the venting flow rate ofthe heated steam 36 fed into the venting pipe within the range of 0.5 to1% of the total flow rate measured before the heated steam 36 is vented.

A fluid resistor that can provide the same effect as described above mayalso be used in place of the pressure control valve.

In this way, the flow amount of the heated steam 36 fed to each U-shapedpipe 2 can be properly adjusted due to the provision of the venting pipeand the pressure control valve. Specifically, the adjustment of theventing flow rate of the heated steam 36 at 0.5% or greater, as comparedwith the total flow rate measured before the heated steam 36 is ventedcan prevent the flow rate of the heated steam 36 fed into each U-shapedpipe 2 from being unduly increased, thereby to avoid excessivegeneration of condensed drain due to excessively rapid condensation ofthe heated steam 36 in the U-shaped pipe 2. In addition, the adjustmentof the venting flow rate of the heated steam 36 at 1% or lower, ascompared with the total flow rate measured before the heated steam 36 isvented, can prevent the flow rate of the heated steam 36 to be fed intoeach U-shaped pipe 2 from being insufficient for the heating process,thereby suppressing degradation of the thermal efficiency of thehygroscopic moisture separating and heating apparatus 20.

Next, the operation of this embodiment constructed as described abovewill be discussed.

In FIG. 2, the steam 35 to be heated, which is fed in the lowertemperature area 30 in the main body container 1 via the steam inlet 6,is fed upward in the lower temperature area 30, and the hygroscopicmoisture is removed from the steam 35, due to the hygroscopic moistureseparator 8 provided in the main body container 1.

The steam 35 to be heated, having passed through the hygroscopicmoisture separator 8, is first heated by the heated steam 36 at thelower temperature area retracting part 221 of the U-shaped pipe 2, andis then heated by the heated steam 36 at the lower temperature areaadvancing part 211 of the U-shaped pipe 2. Subsequently, the steam 35 tobe heated, having been heated in this manner in the lower temperaturearea 30, passes through the space 32 provided between the innercircumferential face of the ceiling of the main body container 1 and thepartition plate 5. Thereafter, the steam 35 to be heated is fed downwardthrough the higher temperature area 31, and is heated by the heatedsteam 36 in the higher temperature area advancing part 212 of theU-shaped pipe 2 and then further heated by the heated steam 36 in thehigher temperature area retracting pipe 222 of the U-shaped pipe 2. Inthis way, the steam 35 to be heated, having been further heated in thehigher temperature area 31, is discharged to the outside of the mainbody container 1 via the steam outlet 7.

As shown in FIG. 4, the temperature of the steam 35 to be heated, forwhich heat exchange with the heated steam 36 flowed through the U-shapedpipe 2 is performed, is the highest, when the heated steam 36 is flowedthrough the higher temperature area retracting part 222, and is lowerthan that case, when the heated steam 36 is flowed through the highertemperature area advancing part 212, further lower, when it is flowedthrough the lower temperature area advancing part 211, and is thelowest, when through the lower temperature area retracting part 221.

As described above, due to the division of the internal space of themain body container 1 into the lower temperature area 30 and the highertemperature area 31 by using the partition plate 5, the regions in whichthe steam 35 to be heated is in contact with the U-shaped pipe 2 can bemore fractioned. For example, in the retracting part 22, a part, uponbeing at the lowest temperature, of the steam 35 to be heated contactswith the lower temperature area retracting part 221, while a part, uponbeing at the highest temperature, of the steam 35 to be heated contactswith the higher temperature area retracting part 222, thereby levelingthe temperature of the steam 35 to be heated through the contact withthe entire retracting part 22.

In this manner, the difference of average temperatures of the steam 35to be heated, upon performing the heat exchange with the heated steam36, can be lessened between the advancing part 21 and the retractingpart 22 of the U-shaped pipe 2. Thus, the difference of the amount ofcondensation caused by cooling the heated steam 36 can be reducedbetween the advancing part 21 and the retracting part 22.

The heating process for the steam 35 to be heated in the main bodycontainer 1 will be described in more detail with reference to FIG. 4.As shown in FIG. 4, in the outermost circumferential U-shaped pipe 201located at the outermost circumference of each pipe bundle 4, when thesteam 35 to be heated is flowed in the main body container 1, the partA, upon being at the lowest temperature, of the steam 35 to be heatedcontacts initially with the lower temperature area retracting part 221of the outermost circumferential U-shaped pipe 201, and then a part B,heated to an intermediate temperature, of the steam 35 contacts with thelower temperature area advancing part 211. Thereafter, a part C, heatedto a further elevated temperature, of the steam 35 contacts with thehigher temperature area advancing part 212 of the outermostcircumferential U-shaped pipe 201, and finally the part D, upon being atthe highest temperature, of the steam 35 contacts with the highertemperature area retracting part 222.

On the other hand, in an innermost circumferential U-shaped pipe 202located at the innermost circumference of each pipe bundle 4, a part E,upon being at a sub-lowest temperature slightly higher than the lowesttemperature part A, of the steam 35 to be heated contacts with the lowertemperature area retracting part 221 of the innermost circumferentialU-shaped pipe 202, and then a part F, heated to a sub-intermediatetemperature slightly lower than the intermediate temperature part B, ofthe steam 35 contacts with the lower temperature area advancing part211. Thereafter, a part G, further heated to a temperature slightlyhigher than the part C, of the steam 35 contacts with the highertemperature area advancing part 212 of the innermost circumferentialU-shaped pipe 202, and finally a part H, upon being at a sub-highesttemperature slightly lower than the highest temperature part D, of thesteam 35 contacts with the higher temperature area retracting part 222.

Now, the comparison of the temperatures of the steam 35 to be heated,when it contacts with the outermost circumferential U-shaped pipe 201and with the innermost circumferential pipe 202, will be discussed.

First, the comparison between the retracting part 22 of the outermostcircumferential U-shaped pipe 201 and the retracting part 22 of theinnermost circumferential U-shaped pipe 202 will be described. As shownin FIG. 4, the average of the temperatures of the lowest temperaturepart A and highest temperature part D of the steam 35 when it contactswith the outermost circumferential U-shaped pipe 201 and the average ofthe temperatures of the sub-lowest temperature part E and sub-highesttemperature part H of the steam 35 when it contacts with the innermostcircumferential U-shaped pipe 202 are substantially the same.

Similarly, the comparison between the advancing part 21 of the outermostcircumferential U-shaped pipe 201 and the advancing part 21 of theinnermost circumferential U-shaped pipe 202 reveals the fact that theaverage of the temperatures of the steam 35 to be heated when itcontacts with the outermost circumferential U-shaped pipe 201 and theaverage of the temperatures of the steam 35 to be heated when itcontacts with the innermost circumferential U-shaped pipe 202 aresubstantially the same.

Accordingly, from the comparison between the averages of thetemperatures of the steam 35 to be heated when it contacts with therespective U-shaped pipes 2, it can be seen that the difference in thetemperature average of the respective U-shaped pipes 2 can be lessenedand equalized. As such, the difference in the amount of condensation ofthe heated steam 36 in the respective U-shaped pipes 2 can also bereduced.

As described above, the difference in the amount of condensation of theheated steam 36 between the advancing parts 21 and between theretracting parts 22 of each U-shaped pipe 2 provided in the main bodycontainer 1 as well as the difference in the amount of condensation ofthe heated steam 36 between the respective U-shaped pipes 2 can belessened, thereby to avoid excessive generation of condensed drain dueto excessively rapid condensation of the heated steam 36 in theadvancing parts 21 as well as in the retracting parts 22. Thus, theventing flow rate of the heated steam 36 fed to the venting pipe can besignificantly lessened.

Therefore, the flow rate of the heated steam 36 supplied into therespective U-shaped pipes 2 in order to heat the steam 35 to be heatedcan be increased so much, as such the thermal efficiency of thehygroscopic moisture separating and heating apparatus 20 can be securelyenhanced.

In the case of assembling the hygroscopic moisture separating andheating apparatus 20, the pipe bundles 4 are prepared by assembling theplurality of U-shaped pipes 2 and headers 3 in advance in a factory, andthen attached to the main body container 1 on a site of installing thehygroscopic moisture separating and heating apparatus 20.

By utilizing such an assembling method, the transport of the componentsto the site of installation can be facilitated, and the period of timerequired for the installation at the site can be reduced.

Second Embodiment

Next, a second embodiment of the present invention will be describedwith reference to FIGS. 5 and 6.

FIG. 5 is a top view showing a construction of the hygroscopic moistureseparating and heating apparatus 40 of the second embodiment when viewedfrom above, and FIG. 6 is a longitudinal cross section of thehygroscopic moisture separating and heating apparatus 40 taken alongline C-C of FIG. 5.

As shown in FIGS. 5 and 6, the hygroscopic moisture separating andheating apparatus 40 of this embodiment includes a main body container 1having a cylindrical shape, a first partition plate 16 provided in themain body container 1 orthogonally to the longitudinal direction of themain body container 1 and configured to divide the internal space of themain body container 1 into two or more mutually independent areas 33,and a second partition plate 15 provided, in the main body container 1,to define a space 32 together with an inner circumferential face of aceiling of the main body container 1 and configured to extendorthogonally to the first partition plate 16 and divide each independentarea 33 of the main body container 1 into a lower temperature area 30and a higher temperature area 31. Steam inlets 6 are respectivelyprovided below the lower temperature areas 30 of the main body container1, through which steam 35 to be heated is fed into the main bodycontainer 1, and steam outlets 7 are respectively provided below thehigher temperature areas 31 of the main body container 1, through whichthe steam 35 to be heated is discharged from the main body container 1.A hygroscopic moisture separator 8 is located in each lower temperaturearea 30 of the main body container 1, the separator 8 being adapted toseparate hygroscopic moisture from the steam 35 fed into the lowertemperature area 30 from each steam inlet 6. In addition, U-shaped pipes2 are provided in each independent area 33 of the main body container 1,orthogonally to the longitudinal direction of the main body container 1.For each U-shaped pipe 2, heated steam 36 is fed so as to heat the steam35 to be heated. The plurality of U-shaped pipes 2 and headers 3constitute together each pipe bundle 4, and for example, six pipebundles 4 are provided in the hygroscopic moisture separating andheating apparatus 40.

In the second embodiment shown in FIGS. 5 and 6, like parts in the firstembodiment as shown in FIGS. 1 to 3 are respectively designated by likereference numerals, and will not be detailed below.

In such a hygroscopic moisture separating and heating apparatus 40, asshown in FIG. 5, the lower temperature area 30 in one independent area33 is adjacent to the higher temperature area 31 in the otherindependent area 33. The advancing part 21 and the retracting part 22 ofeach U-shaped pipe 2 extend through the second partition plate 15 acrosseach lower temperature are 30 and each higher temperature area 31.

According to the hygroscopic moisture separating and heating apparatus40 of this embodiment, in addition to the effect obtained in the firstembodiment, the following effect can be obtained. Namely, each U-shapedpipe is provided orthogonally to the longitudinal direction of the mainbody container 1, as such each advancing part 21 and each retractingpart 22 can be shortened. Therefore, each pipe bundle 4 can bedownsized, thus facilitating the transfer of the pipe bundles 4 to thesite of installation. Additionally, since the internal space of the mainbody container 1 is divided into the plurality of independent areas 33,and the lower temperature area 30 of one independent area 33 is locatedadjacent the higher temperature area 31 of the other independent area33, the temperature distribution in a horizontal plane of the main bodycontainer 1 can be securely leveled, thereby preventing significantthermal deformation of the main body container 1.

Third Embodiment

Next, a third embodiment of the present invention will be described withreference to FIGS. 7 and 8.

FIG. 7 is a lateral cross section showing a supply route for supplyingheated steam 36 to each U-shaped pipe 2 of the hygroscopic moistureseparating and heating apparatus 40 of the third embodiment, and FIG. 8is a longitudinal cross section of the supply route for the heated steam36 taken along line D-D of FIG. 7. In the third embodiment shown inFIGS. 7 and 8, like parts in the first embodiment and the secondembodiment are respectively designated by like reference numerals, andwill not be detailed below.

In the hygroscopic moisture separating and heating apparatus 40 of thisembodiment, as shown in FIG. 7, the plurality of pipe bundles 4 arelocated in a plurality of independent groups connected in series withone another, and the pipe bundles 4 in each group are connected inparallel to one another, with the number of the pipe bundles 4 in eachgroup being reduced as the heated steam 36 is flowed from the upstreamto the downstream. The remaining construction, however, is substantiallythe same as the second embodiment shown in FIGS. 5 and 6.

As shown in FIG. 7, the plurality of pipe bundle 4 are divided into twobundles 4 constituting together an upstream group 41 and provided inparallel to each other and one pipe bundle 4 constituting a downstreamgroup 42.

In FIG. 7, the heated steam 36 essentially consisting of extractionsteam to be supplied from a high pressure turbine of an atomic powerplant or of main steam to be supplied from a nuclear reactor is suppliedinto two headers 3 of the two pipe bundles 4 provided in parallel toeach other and constituting the upstream group 41, via an upstreamheated steam supply piping 24. Thereafter, the heated steam 36discharged from the headers 3 of the two pipe bundles 4 of the upstreamgroup 41 is supplied into the header 3 of the one pipe bundle 4constituting the downstream group 42 via a downstream heated steamsupply piping 25. Subsequently, the heated steam 36 discharged from theheader 3 of the one pipe bundle 4 of the downstream group 42 is fed tothe outside of the hygroscopic moisture separating and heating apparatus40 via a heated steam exhaust piping 26.

The header 3 of each pipe bundle 4 includes a heated steam inlet 9 forreceiving the heated steam 36 to be fed from the upstream side and aheated steam outlet 11 for discharging the heated steam 36 to thedownstream side.

While, in FIG. 7, the upstream group 41 is composed of the two pipebundles 4 and the downstream group 42 is composed of the one pipe bundle4, the number of the pipe bundles 4 in each group is not limited to thisaspect, provided that it is reduced as the heated steam 36 is flowedfrom the upstream to the downstream. For instance, the number of thepipe bundles 4 depends on the length of each U-shaped pipe 2 as well ason the flow speed of the heated steam 36 in the U-shaped pipe 2.

As shown in FIG. 8, a drain tank 101 is provided, which is foraccumulating condensed drain generated due to the heated steam 36 cooledby the steam 35 to be heated, in each U-shaped pipe 2, and a drain pipe10 adapted for feeding the condensed drain to the drain tank 101 isprovided to the header 3 of each pipe bundle 4.

Now, the operation of the embodiment constructed as described above willbe discussed.

The heated steam 36 fed into the hygroscopic moisture separating andheating apparatus 40 is first supplied into the two parallel pipebundles 4 of the upstream group 41, simultaneously, via the upstreamheated steam supply piping 24, so as to perform the heat exchange withthe steam 35 to be heated in the main body container 1. Thereafter, theheated steam 36 discharged from the two pipe bundles 4 of the upstreamgroup 41 is fed into the one pipe bundle 4 of the downstream group 42via the downstream heated steam supply piping 25, so as to perform againthe heat exchange with the steam 35 to be heated in the main bodycontainer 1. Finally, the heated steam 36 discharged from the one pipebundle 4 of the downstream group 42 is fed to the outside of thehygroscopic moisture separating and heating apparatus 40 via the heatedsteam exhaust piping 26.

Meanwhile, the condensed drain is generated due to the heated steam 36cooled by the steam 35 to be heated in the U-shaped pipe 2 of each pipebundle 4. However, the so-generated condensed drain in each pipe bundle4 is fed to each drain pipe 10 attached to each header 3 andcollectively accumulated in the drain tank 101.

In this way, by limiting the number of pipe bundles 4 each adapted tofeed the heated steam 36 at a time and discharging the condensed drainfrom the pipe bundles 4 of each group, in succession, by utilizing eachdrain pipe 10, the flow rate of the heated steam 36 in each U-shapedpipe 2 of the pipe bundles 4 can be increased, as well as overfilling ofthe condensed drain in each U-shaped pipe 2 of the pipe bundles 4 can beprevented.

Alternatively, a part of the condensed drain fed into the drain tank 101from each header 3 of the pipe bundles 4 via each drain pipe 10 may befed back through each higher temperature area 31 of the main bodycontainer 1, by utilizing a drain feed pipe 102 so as to cool the highertemperature area 31.

By employing the method as described above, the temperature differencebetween each lower temperature area 30 and each higher temperature area31 can be lessened, as well as the temperature distribution in ahorizontal plane of the main body container 1 can be securely leveled.

1. A hygroscopic moisture separating and heating apparatus forseparating a hygroscopic moisture from a steam to be heated and heatingthe steam to be heated, comprising: a main body container having acylindrical shape; a partition plate provided, in the main bodycontainer, to define a space together with an inner circumferential faceof the main body container and configured to divide the internal spaceof the main body container into a lower temperature area and a highertemperature area; a steam inlet, which is provided to the lowertemperature area of the main body container and through which steam tobe heated is fed into the main body container; and a steam outlet, whichis provided to the higher temperature area of the main body containerand through which the steam to be heated is discharged from the mainbody container; a hygroscopic moisture separator located in the lowertemperature area of the main body container and adapted to separatehygroscopic moisture from the steam to be heated, which is fed into thelower temperature area via the steam inlet; and a U-shaped pipe providedin the main body container and including an advancing part, a retractingpart and a U-shaped part connecting the advancing part with theretracting part, such that heated steam for heating the steam to beheated is fed through the U-shaped pipe, wherein either of the advancingpart and the retracting part of the U-shaped pipe extends through thepartition plate across the lower temperature area and the highertemperature area.
 2. The hygroscopic moisture separating and heatingapparatus, according to claim 1, wherein the partition plate is providedorthogonally to the longitudinal direction of the main body container,and wherein the advancing part and the retracting part of the U-shapedpipe are arranged parallel to the longitudinal direction of the mainbody container.
 3. The hygroscopic moisture separating and heatingapparatus, according to claim 1, further comprising: a venting pipeconnected with an inlet portion of the U-shaped pipe and adapted forventing the heated steam; and a pressure control valve or fluid resistorprovided to the venting pipe, wherein the pressure control valve orfluid resistor controls the venting flow rate of the heated steam fedinto the venting pipe within the range of 0.5 to 1% of the total flowrate measured before the heated steam is vented.
 4. The hygroscopicmoisture separating and heating apparatus, according to claim 1, whereina plurality of U-shaped pipes are provided; wherein each U-shaped pipeis attached to a header so as to constitute together a pipe bundle, theheader being provided outside the main body container and adapted tosupply and discharge the heated steam, and wherein the header of onepipe bundle is attached to the main body container, in a positionopposed to the header of the other pipe bundle located adjacent the onepipe bundle.
 5. The hygroscopic moisture separating and heatingapparatus, according to claim 4, wherein the plurality of pipe bundlesare located in a plurality of independent groups connected in serieswith one another, and the pipe bundles in each group are connected inparallel to one another, with the number of the pipe bundles in eachgroup being reduced as the heated steam is flowed from the upstream tothe downstream, wherein a drain tank is provided, which is adapted foraccumulating condensed drain generated due to the heated steam cooled bythe steam to be heated, in each U-shaped pipe, and wherein the draintank is connected with the header of each pipe bundle via a drain pipe.6. The hygroscopic moisture separating and heating apparatus, accordingto claim 5, wherein a part of the condensed drain fed to the drain tankvia the drain pipe from each header is fed into the higher temperaturearea of the main body container through a drain feed pipe, so as to coolthe higher temperature area.
 7. The hygroscopic moisture separating andheating apparatus, according to claim 1, wherein the pipe bundles areprepared by assembling the plurality of U-shaped pipes and headers inadvance in a factory, and then attached to the main body container on asite of installing the apparatus.
 8. A hygroscopic moisture separatingand heating apparatus for separating a hygroscopic moisture from a steamto be heated and heating the steam to be heated, comprising: a main bodycontainer having a cylindrical shape; a first partition plate providedin the main body container orthogonally to the longitudinal direction ofthe main body container and configured to divide the internal space ofthe main body container into two or more mutually independent areas; asecond partition plate provided, in the main body container, to define aspace together with an inner circumferential face of the main bodycontainer and configured to extend orthogonally to the first partitionplate and divide each independent area of the main body container into alower temperature area and a higher temperature area; steam inlets eachprovided to each lower temperature area of the main body container, suchthat steam to be heated is fed into the main body container through thesteam inlet; steam outlets each provided to each higher temperature areaof the main body container, such that the steam to be heated isdischarged from the main body container through the steam outlet;hygroscopic moisture separators each located in each lower temperaturearea of the main body container and adapted to separate hygroscopicmoisture from the steam to be heated fed into the lower temperature areavia each steam inlet; and U-shaped pipes each provided in eachindependent area of the main body container and including an advancingpart, a retracting part and a U-shaped part connecting the advancingpart with the retracting part, such that heated steam for heating thesteam to be heated is fed through the U-shaped pipe, wherein the lowertemperature area of one independent area is adjacent to the highertemperature area of the other independent area, and wherein either ofthe advancing part and the retracting part of each U-shaped pipe extendsthrough the second partition plate across each lower temperature areaand each higher temperature area.
 9. The hygroscopic moisture separatingand heating apparatus, according to claim 8, further comprising: aventing pipe connected with an inlet portion of each U-shaped pipe andadapted for venting the heated steam; and a pressure control valve orfluid resistor provided to the venting pipe, wherein the pressurecontrol valve or fluid resistor controls the venting flow rate of theheated steam fed into the venting pipe within the range of 0.5 to 1% ofthe total flow rate measured before the heated steam is vented.
 10. Thehygroscopic moisture separating and heating apparatus, according toclaim 8, wherein a plurality of U-shaped pipes are provided; whereineach U-shaped pipe is attached to a header so as to constitute togethera pipe bundle, the header being provided outside the main body containerand adapted to supply and discharge the heated steam, and wherein theheader of one pipe bundle is attached to the main body container, in aposition opposed to the header of the other pipe bundle located adjacentthe one pipe bundle.
 11. The hygroscopic moisture separating and heatingapparatus, according to claim 10, wherein the plurality of pipe bundlesare located in a plurality of independent groups connected in serieswith one another, and the pipe bundles in each group are connected inparallel to one another, with the number of the pipe bundles in eachgroup being reduced as the heated steam is flowed from the upstream tothe downstream, wherein a drain tank is provided, which is adapted foraccumulating condensed drain generated due to the heated steam cooled bythe steam to be heated, in each U-shaped pipe, and wherein the draintank is connected with the header of each pipe bundle via a drain pipe.12. The hygroscopic moisture separating and heating apparatus, accordingto claim 11, wherein a part of the condensed drain fed to the drain tankvia the drain pipe from each header is fed into each higher temperaturearea of the main body container through a drain feed pipe, so as to coolthe higher temperature area.
 13. The hygroscopic moisture separating andheating apparatus, according to claim 8, wherein the pipe bundles areprepared by assembling the plurality of U-shaped pipes and headers inadvance in a factory, and then attached to the main body container on asite of installing the apparatus.